How to use
Beacons are usually teamed up with a Target Teleporter. The Beacon determines the endpoint for the teleportation.
How to Obtain
Beacons can be crafted, or acquired as loot. If they drop as loot, a Target Teleporter will always drop at the same time. You can also trade for this item on a market world.
How to Use
To set up a Target Teleporter, you must also have a Beacon. First decide the location you want to start from, and place the Target Teleporter on that spot. Decide where you want the player to transport to, and place the Beacon in that location. You will know that it worked if the Target Teleporter has a blue fire coming from the base.
Your Engineering skill determines how far you can teleport; multiply your Engineering skill by 10 to calculate the maximum distance you can place the two apart. For example, if your Engineering is 6: 6 x 10 = 60 blocks. If your Engineering skill is maxed out at 15: 15 x 10 = 150 blocks.
Beacons are also used to relocate world machines like the mass teleporter and mass spawner. Click on the machine, select the option for moving it, then place the beacon where you want the bottom left corner of the machine to go. Moving the machine will consume the beacon.
Just like how you set up Beacons and Target Teleporters like switches and doors, you can use a special trick to link multiple Target Teleporters to a single Beacon. To accomplish this, you must first place a Target Teleporter and a Beacon in their respective desired locations as described above. Next, mine the Beacon (DO NOT TOUCH THE TELEPORTER). The blue fire on the Target Teleporter will go out, but just be patient. Now, place a second Target Teleporter in the second desired location and then place the Beacon back in the exact same spot you did initially. If you did everything correctly, you should have 2 Target Teleporters linked to a single Beacon (destination).